Patients with allergic asthma due to one or more of ragweed, plantain, grasses, oak, maple, dust mites, Alternaria, Cladosporium, cat, and dog are to be treated with either standardized allergen extracts or placebo injections. The following changes will be evaluated before and two times after treatment: 1) bronchial inflammation by biopsy and BAL 2) late phase inflammatory cell numbers in BAL fluids after bronchial segmental allergen challenge 3) mediator levels, cytokine gene expression, and cytokine in bronchoalveolar lavage fluids after both early and late bronchial segmental allergen challenge 4) symptom reporting of asthma 5) medication use 6) two times daily peak expiratory flow rates 7) immediate and late responses to inhaled provocation with allergen 8) non specific hyperreactivity to methacholine 9) immediate and late phase skin responses 10) IgE and IgG antibody levels.